Amherst couple demonstrates domes' potential in their backyard

AMHERST -- It just so happens that the strongest structure made my man, the geodesic dome, also makes for one heck of a great design for a greenhouse.

Through their new company, Clint and Britt Ellsworth are using the domes to create year-round environments for gardening.

The Ellsworths are the owners of www.harvestpathway.com, a company that specializes in both greenhouse dome kits and custom-built geodesic domes. The structures range in size from as small as 10 feet in diameter to almost as large as the imagination (and local zoning regulations) will permit.

The domes are fashioned of pine two-by-fours and are covered in a material manufactured in Germany called SolaWrap, which resembles bubble wrap and offers incredible energy efficiency, light diffusion, and durability. According to the Ellsworths, who have the exclusive rights to sell SolaWrap in North America, the material can withstand heavy snow loads and won't buckle under gale-force winds.

"My father builds these domes in Alaska and they've survived storms with 135 mile-per-hour winds," said Clint. "Because of their shape and the material, the wind just goes right over them. There's nothing for the wind to grab onto."

The Ellsworths first got into building the domes when Britt's parents said they wanted one.

"We found a book online. It was horribly written and had bad instructions, but after we fixed a few errors in the math, we figured it out," said Clint. With the help of his dad, they built their first dome, and they realized they were onto something special.

On their own property in Amherst, the Ellsworths decided to put their design to the test in a big way, and they erected a massive dome that spans 38 feet in diameter. And though it's impressive from the outside, it's the aquaponic design inside that is truly remarkable.

On one side of the dome is a large tank and that's fed by a waterfall. In that tank, the Ellsworth will be raising tilapia, a white fish. The water from the fish tank, laced with natural fertilizer, will then circulate through a bed of gravel that runs along the inside of the dome.

In this gravel, the Ellsworths will grow a variety of vegetables and fruits year-round including leafy greens, strawberries, and tomatoes. As the water moves through the gravel, it will deposit the fertilizer and get filtered before returning to the fish tank.

But fish and leafy greens aren't enough to satisfy a New Englander's hunger, so in the center of the dome, the Ellsworths have constructed a dirt bed where onions, potatoes, carrots and other root vegetables will grow. The beds are all built waist-high so there'll be no bending over to plant or harvest, and the gravel beds won't grow weeds so that chore is eliminated from gardening.

Because of the shape of the dome, the building gets sunlight from whatever direction the sun is heading, and on a warm March day, the temperatures inside the dome reached well over 100 degrees. But on cold winter days, the Ellsworths will heat the structure with what's called a "rocket mass heater."

The heater is essentially a barrel with a convection system built inside. But unlike a traditional wood stove, the chimney is at the bottom of the barrel and is channeled through a brick and gravel "bench" which absorbs the heat from the exhaust. By the time the smoke is vented outside, most of its heat is left inside the building.

"It's an incredibly efficient source of heat," said Britt. "You can use sticks instead of logs and get the same amount of heat."

Work is almost completed on the Ellsworths' own private biodome, and they'll begin growing soon. But in the meantime, they're meeting the demand for the dome kits by outsourcing manufacturing to a company in Pennsylvania. But their hands will still be getting dirty on the custom domes, Clint said.